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(11) | EP 0 244 366 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Self-aligned process for fabricating small size DMOS cells and MOS devices obtained by means of said process |
(57) Described is an improved fabrication process for vertical DMOS cells contemplating
the prior definition of the gate areas by placing a polycrystalline silicon gate electrode
and utilizing the gate electrode itself as a mask for implanting and diffusing the
body regions, while forming the short region is carried out using self-Âalignment
techniques which permit an easy control of the lateral extention of the region itself.
A noncritical mask defines the zone where the short circuiting contact between the
source electrode and the source and body regions in the middle of the DMOS cell will
be made, allowing also to form the source region. Opening of the relative contact
is also effected by self alignment techÂnique, further simplifying the process. |